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Abstract Non‐isothermal thermogravimetric analysis in air, of polyoctenamer‐single wall carbon nanotubes (PO‐SWNTs), loaded by various amounts of SWNTs up to 10% wt., at different heating rates (ranging from 5 to 40°C/min) is reported. The thermal degradation in the air of PO_SWNTs is dominated by a main single sigmoidal dependence, assigned to the polymer and eventually polymer‐nanofiller interphase, over which a weaker sigmoid assigned to the thermo‐oxidative degradation of the nanofiller is superimposed at higher temperatures. The temperature at which the nanocomposite's residual mass fraction reachesx% wt. of the initial mass,T_x%, is reported (forx = 5, 50, and 85). The dependence ofT_x%on the heating rate and the loading by nanotubes is analyzed. The temperature derivative of the thermograms defines new parameters (inflection residual mass fraction and inflection temperature) and (degradation) width. Their dependence on the loading by SWNTs was reported. Estimation of the interphase in polymer‐based nanocomposites is based on the postulate that the dependence of the inflection temperature on the composition of the nanocomposite obeys a Fox‐like dependence, where the bulk polymer and the polymer trapped within the interphase are considered as a blend of two miscible polymers. Complementary Raman, x‐ray diffraction, and differential scanning calorimetry support these results. 

Abstract Thermogravimetric analysis of polyethylene oxide (powder and nanofibers obtained by force spinning water or chloroform solutions of polyethylene oxide) was studied using different theoretical models such as Friedman and Flynn‐Wall‐Ozawa. A semiempirical approach for estimating the “sigmoid activation energy” from the thermal degradation was suggested and confirmed by the experimental data on PEO powder and nanofibers' mats. The equation allowed for calculating a “sigmoid activation energy” from a single thermogram using a single heating rate without requiring any model for the actual complex set of chemical reactions involved in the thermal degradation process. For PEO (powder and nanofibers obtained from water solutions), the “sigmoid activation energy” increased as the heating rate was increased. The sigmoid activation energy for PEO mats obtained from chloroform solutions exhibited a small decrease as the heating rate was increased. Thermograms' derivatives were fitted to determine the coordinates of the inflection points. The “sigmoid activation energy” was compared to the activation energy determined from the Flynn‐Wall‐Ozawa model. Similarities between the thermal degradation of polyethylene oxide powder and of the nanofibers obtained from water solutions were discussed. Significant differences between the sigmoid activation energies of the mats obtained from water and chloroform solutions were reported.